Xiaolong Deng

Quantum Computing (QC) presents a significant departure from and substantial parallels to classical computing. Some such parallels include the need to understand topology and system characteristics information and make that available to users as well as other system components like compilers, runtimes, and schedulers. We analyze the differences and extend sys-sage to capture quantum information. This leverages code reuse and automatically incorporates QC information into the software stack for hybrid HPCQC integration. This paper addresses the extensions to sys-sage, a classical HPC-relevant library, to also represent and store the characteristics of Quantum Processing Units (QPUs). Our work also presents the role of sys-sage in pre-processing and analyzing the topology and properties of different components of QCs to provide valuable insights that compilers, schedulers or circuit mappers can use. These features aim to facilitate the HPCQC ecosystem by providing a unified interface.

Quantum systems have traditionally operated within highly controlled laboratory environments to minimize internal noise and maximize stability. However, when these systems are integrated into High Performance Computing (HPC) environments and setup for continuous operation, they encounter significantly higher levels of external noise and instability coupled with higher demands. This paper introduces a comprehensive framework to counter the challenges of maintaining the stability of operational quantum computers in such noisy HPC settings. We propose a novel system architecture that monitors and manages the environmental conditions of quantum computing systems using a broad set of sensors, enhancing their robustness and reliability. Our architecture is open and can be extended to other setups. It can serve as a blueprint for other sites as it spans quantum technologies and offers broad coverage. Ultimately, this data will be essential to facilitate advancements in machine learning to drive real-time error mitigation.

As quantum system mature and make their way out of physics laboratories into production facilities, we also need to push the development of the matching development and operational, in short DevOps, environments. While programming systems are often in forefront when talking about development environments for quantum systems, DevOps must cover many more aspects, which are often not covered. In this short paper, we will discuss what components are needed and describe our approaches to establish these components. The result is a first step towards an open, widely accessible and usable DevOps environment, which will form the basis to continue to drive the evolution of quantum systems.

Strong enough intersite interactions may result in lack of ergodicity in disorder-free many-body lattice systems. Ultracold dipolar gases in optical lattices provide an experimentally accessible platform for exploring this physics. Dipolar intersite interactions are usually assumed to decay with a fixed power law. We show that in a one-dimensional polar lattice gas the actual decay depends on the transversal confinement. This affects profoundly the particle dynamics, which mimics rather that of a system with an externally controllable effective power-law interaction. Our results show that the crucial role of the interaction decay on disorder-free localization may be flexibly studied in experiments with polar gases.

We consider a 2d dipolar system, d=2 d = 2 , with the generalized dipole-dipole interaction \sim r^{-a} ∼ r − a , and the power a a controlled experimentally in trapped-ion or Rydberg-atom systems via their interaction with cavity modes. We focus on the dilute dipolar excitation case when the problem can be effectively considered as single-particle with the interaction providing long-range dipolar-like hopping. We show that the spatially homogeneous tilt \beta β of the dipoles giving rise to the anisotropic dipole exchange leads to the non-trivial reentrant localization beyond the locator expansion, a a < d , unlike the models with random dipole orientation. The Anderson transitions are found to occur at the finite values of the tilt parameter \beta = a β = a , 0 0 < a < d , and \beta = a/(a-d/2) β = a / ( a − d / 2 ) , d/2 d / 2 < a < d , showing the robustness of the localization at small and large anisotropy values. Both exact analytical methods and extensive numerical calculations show power-law localized eigenstates in the bulk of the spectrum, obeying recently discovered duality a\leftrightarrow 2d-a a ↔ 2 d − a of their spatial decay rate, on the localized side of the transition, a>a_{AT} a > a A T . This localization emerges due to the presence of the ergodic extended states at either spectral edge, which constitute a zero fraction of states in the thermodynamic limit, decaying though extremely slowly with the system size.

Sufficiently strong intersite interactions in extended-Hubbard and XXZ spin models result in dynamically bound clusters at neighboring sites. We show that the dynamics of these clusters in two-dimensional lattices is remarkably different and richer than that of repulsively bound on-site clusters in gases without intersite interactions. Whereas on-site pairs move in the same lattice as individual particles, nearest-neighbor dimers perform an interacting quantum walk in a different lattice geometry, leading to a peculiar dynamics characterized by multiple timescales. Although this is generally true, it is especially relevant in some lattices, including triangular and diamond lattices for hard-core bosons, and square lattices for soft-core bosons, where dimers move resonantly in either a kagome or a Lieb lattice. As a result, dimers show two very different transport velocities—a fast one comparable to the motion of individual particles, and a very slow one associated to flatband quasilocalization. Moreover, these lattices permit the resonant motion of longer clusters, and, remarkably, trimers move faster than quasi-flatband dimers for sufficiently strong optical lattices. This rich interplay between multiscaled quantum walk dynamics, quasilocalization, and flatband physics may be readily observed in experiments with lanthanide atoms.